Operations and maintenance costs represent a major portion of a typical utility company's budget. Utility excavations as they are performed today are very labor-intensive and disruptive, but they are necessary to repair aging infrastructure and install new equipment. Multiple crews are required to perform utility locating, mark-out, excavation, sheeting and shoring, and restoration. Additional staff are engaged to support the excavation, including project managers, vehicle drivers, equipment operators, and administrative personnel. A single excavation may represent a major investment of time, money, personnel, and equipment. The costs of these excavations are often passed-on to the utility customer.
Engaging large crews to perform excavations requires dedicating resources to labor-intensive projects. In spite of technological advances that offer improvements in cost and productivity in some areas, utility excavations are still performed today in much the same way that they have been for decades. Typical utility excavations require deploying multiple large vehicles, heavy equipment, and multiple crews. The large site-footprint required for utility vehicles and heavy excavating equipment can create a public nuisance and cause major disruptions to traffic. Construction equipment and utility vehicles also have fuel economies which are significantly worse than those of passenger vehicles, leading excavation sites to have not only a large physical footprint, but a substantial carbon footprint as well. Reducing the excavation site's physical and carbon footprints would provide a positive environmental impact, reduce costs, and serve as a benefit to the public.
Prior to an excavation, mark-out crews are called to locate underground utilities. Mark-out crews use maps to locate key pipeline features and main-line routing from above ground. Once the maps are consulted, mark-out crews use spray paint on the road surface to mark the location of pipeline features prior to excavation; however, the mark-outs provided are only as accurate as the data which is available to the utility company or mark-out crew. Maps and as-built construction drawings are often inaccurate, or do not represent decades of subsequent maintenance, repair and replacement activities which have occurred. Changes to street and sidewalk layout, the construction of new buildings, the installation of new gas and other utility services, the demolition of old buildings, and other changes over the years can make it difficult to translate the old maps to the current street configuration. In addition, the underground networks of major cities can be very crowded with gas, steam, sewer, water, electrical, telecommunications, and other utilities running in close proximity to one another. These underground networks are often inadequately mapped and the locations of different utility infrastructure installed below street level are almost never integrated on the same map. This lack of integration can lead to many problems.
Damage to buried utilities can occur when the excavator is not aware, either through negligence or incomplete information, of what lies beneath the road surface. This damage is typically described in relation to the level of involvement of the utility infrastructure owner. For example, a common form of damage is referred to as “third party damage” to indicate that it is not the fault of the utility which owns the damaged infrastructure—i.e., the first party—or a direct contractor of that utility—i.e., the second party—but instead is the fault of an unaffiliated excavator—for example, a telecommunications utility crew striking and damaging natural gas infrastructure. Unfortunately, first and second parties are not immune from damaging their own infrastructure, either through insufficient excavation techniques or by not identifying the location of all buried utilities while excavating. For all of these reasons, an improved method of performing utility excavations is needed to reduce or eliminate the aforementioned problems.